The organelle responsible for keeping the cell clean is the cell membrane.
Answer: New vaccines are offered each year because the virus changes.
Explanation: The flue viral strain constantly changes its genetic make up, a process called antigenic drift. As the virus replicates there are small changes that creates new strains which evolve to a completely different influenza virus requiring a new type of vaccine each year.
Answer:
Revolution of earth around the sun
Explanation:
Answer:
A cryptogam is a plant that reproduces by spores, without flowers or seeds. "Cryptogamae" means hidden reproduction, referring to the fact that no seed is produced, thus cryptogams represent the non-seed bearing plants. Other names, such as "thallophytes", "lower plants", and "spore plants" are also occasionally used.
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